Before Hitchhiker was a best-selling book, itwas a radio show that first aired on March 8, 1978, on BBC Radio 4. It was billed as “an epic adventure in time and space including some helpful advice on how to see the Universe for less than 30 Altairian dollars a day” (the main currency of the Milky Way galaxy in the stories).

The franchise soon expanded to include books, a computer game, CDs, cassettes, a TV series, a 2005 movie, and h2g2, which is supposed to be a hitchhiker’s guide to Earth. By the time Adams died of a heart attack at 49 in May 2001, his books had sold more than 14 million copies worldwide.